Incidence and prevalence of Tourette syndrome and chronic tic disorders in Taiwan: a nationwide population-based study

Purpose: The incidence of Tourette syndrome and chronic tic disorders has seldom been evaluated in Asia. Methods: Using the National Taiwan Insurance Research Database, the annual standardized incidence and prevalence of Tourette syndrome (TS) and chronic tic disorders were estimated from 2007 to 2015. The pre-existing comorbidity at disease diagnosis was also evaluated. Results: From 2007 to 2015, the age- and sex-standardized incidence increased from 5.34 (95% confidence interval [CI] 5.06–5.62) per 100,000 person-years to 6.87 (95% CI 6.53–7.21) per 100,000 person-years. In children and adolescents, the age- and sex-standardized incidence increased from 19.58 (95% CI 18.42–20.75) per 100,000 person-years to 31.79 (95% CI 30.09–33.49) per 100,000 person-years. In adults, the age- and sex-standardized incidence decreased from 2.01 (95% CI 1.79–2.23) per 100,000 person-years to 1.24 (95% CI 1.07–1.42) per 100,000 person-years. The incidence rate ratio (IRR) between males and females was 3.74 (95% CI 3.32–4.22). The age- and sex-standardized prevalence increased from 37.51 (95% CI 36.75–38.27) per 100,000 people in 2007 to 84.18 (95% CI 83.02–85.35) per 100,000 people in 2015. The rate risk (RR) between males and females was 3.65 (95% CI 3.53–3.78). Conclusion: The annual incidence rates of TS and chronic tic disorders increased in childhood and adolescence but decreased in adulthood from 2007 to 2015. The prevalence rates increased over the same period.